how to resolve smtp error : sending message?

Question

Below is my code using smtp for sending mail.

MailMessage mm = new MailMessage("user@gmail.com", "user@gmail.com");
mm.Subject = "test";
mm.Body = "hi";
SmtpClient smtp = new SmtpClient("smtp.gmail.com",587);
smtp.Credentials = new NetworkCredential { UserName = "user@gmail.com", Password = "" };
smtp.EnableSsl = true;
smtp.Send(mm);

when am trying to execute this code i got the below error,

please help me to resolve this error..

Thanks in Advance,

Answer 1

Try the following:

• Check if the production server is blocked from making a connection: https://myaccount.google.com/device-activity

• Check if 2-Step verification is enabled, here: https://myaccount.google.com/security If it is not, and you don't want to/need to enable it, you need to allow the application 'less secure' access here: https://myaccount.google.com/lesssecureapps

• If you do want 2-Step verification, you have to generate a special app password and use that in the credentials. You can create this app password when you switch 2-Step verification on.